Avizo files for Oriensmilus liupanensis left skull base

<p>A new genus and species of sabretooth, Oriensmilus liupanensis&nbsp;(Barbourofelinae, Nimravidae, Carnivora), from the middle Miocene of China&nbsp;suggests barbourofelines are nimravids, not felids</p> <p>Since the early 2000s, a revival of a felid relationship for barbourofeline sabretooths has become popular due to recent&nbsp;discoveries of fragmentary fossils from Africa. According to this view, barbourofelines trace their common ancestor&nbsp;with felids through shared similarities in dental morphology going back to the early Miocene of Africa and Europe.&nbsp;However, whether or not such an idea is represented in the basicranial morphology, a conservative area of high&nbsp;importance in family-level relationships, is yet to be tested. A nearly complete skull of Oriensmilus liupanensis gen. and&nbsp;sp. nov. from the middle Miocene Tongxin Basin of northern China represents the most primitive known barbourofeline&nbsp;with an intact basicranial region, affording an opportunity to re-examine the relationship of felids and nimravines. We&nbsp;also present an update on East Asian records of barbourofelines. The new skull of Oriensmilus possesses a suite of&nbsp;characters shared with nimravines, such as the lack of an ossified (entotympanic) bullar floor, absence of an intrabullar&nbsp;septum, lack of a ventral promontorial process of the petrosal, presence of a small rostral entotympanic on the dorsal&nbsp;side of the caudal entotympanic, and a distinct caudal entry of the internal carotid artery and nerve that pierces the&nbsp;caudal entotympanic at the junction of the ossified and unossified caudal entotympanics. The absence of an ossified&nbsp;bullar floor in O. liupanensis and its presence in those from the middle Miocene of Sansan, France thus help to bracket&nbsp;the transition of this character, which must have happened in the early part of the middle Miocene. Spatial relationships&nbsp;between bullar construction and the middle ear configuration of the carotid artery in Oriensmilus strongly resemble&nbsp;those in nimravines but are distinctly different from felids and other basal feliforms. Despite the attractive notion that&nbsp;early barbourofelines arose from a Miocene ancestor that also gave rise to felids, the basicranial evidence argues against&nbsp;this view.</p>